Liquid depth indicator system



Sept 7, 1943. v. H. CONLEY LIQUID DEPTH INDICATOR SYSTEM Filed April 18,1942 4 Sheets-Sheet` l fm D WM M H G O C C f.

X W M vu u w w M M Sep@ A i943. 'v H. coN'LEY v 328995 LIQUID DEPTHINDICATOR SYSTEM v/A Fm m W mm 5 mf pm of 2, -W"NS K my. 4 55 :I: .47@mw s M W W m w y y W m. .m l1: K l .r VIH v m VIVI/#12395 Sept Sept. A1943. v. HgcoNLEY LIQUID DEPTH INDICATOR SYSTEM Filed April 18, 1942 Wfm2 M Patented Sept. 7, 1943 buiten star f accesso y 4traum narrarecorrieron erstere Victor El ilonley, deceased, tate or fbicago, El.,by Mary Eordey, cxecnt in, dlhicagc, lill.

Application April li This invention relates to an improved liquid depthindicating system adapted to conveniently and directly indicate eitherat the liquid container or at remote stations the depth of the liquid inthe container, such, for example, as an automobile gasoline tank, or forindicating the varying levels or depths in the water ballast tanks, orthe bilge or steamships, or the like.,

It is an object of the invention to provide an improved and simplifiedform of an electrically controlled liquid level or depth indicatingsystem wherein air or an inert gas from a liquid compressed diaphragmvtransmits pressure to an inert organic liquid for controlling theoperation of a mercury column topped by a quenching liquid column of aninert organic mobile liquid, which is movable into immersingrelationship with a heated wire arm of an electric bridge unit to varythe resistance of the Wire arm to unbalance the bridge proportions tothe pressure transmitted by the diaphragm to obtain the depth of theliquid compressing the diaphragm.

Another object of the invention is to provide a liquid depth indicatingsystem including a bodyv of mercury disposed between inert .organicliquid control columns governing the operation of a Wheatstone bridgearrangement, one arm or which is varied in eiective length to change theresistance thereof by the operation of one of the control columns tocause operation or an indieating meter to record the level or depth ofliquid being measured'in a container by means or a bellows for producinga pressure for actuating 'all of 'the liquid control columns of thesystem "it is also an object of this invention to provide 9:22, SarlatNo. 429,524

(Clt "film-Stil) unit operable on the Wheatstone bridge principle andincluding abridge arm the effective length of which is vvaried by themovement of a combination liquid control column, one of the liquids ofwhich is movable to submerge a portion oi the arm in amounts directlyproportional Y to the amount of liquid in the tank to produce antuibalanced circuit and cause operationof an indin eating meter to showthe level or the depth or" liquid in the tank being measured.

it is furthermore an object of this invention to provide an improvedliquid depth indicating sys tem for selectively measuring the depth ciliquids in a plurality of separated tanks or containers, said systembeing readily adaptable for use connection with measuring liquid inballast teni/:s ci' ships and for other purposes. The system includes aplurality of protected bellows-like readily read on a meter :orming partoi a master an improved and efficient liquid dep-th indicating system,for selectively indicating the depth of liquids in a plurality of tanksor containers, said system including for the respective tanks orcontainers a closed bellows-like control to be acted upon by the liquidcontent of a tank to cause pressure controlled actuation of an electrictranslater unit involving a Wheatstone bridge principle and beingconnected with an adjacently positioned or remote control case which isconveniently operable to selectively give a depth readu ing of theliquid in a selected tank of a group of tanks, such as the ballast tanksof a steamship.

A further object of the invention is the provision of an improved liquiddepth indicating sys- Y control cabinet to which the various translatorsare connected and whereby the Vdepth of in lthe tanks connected. withthe translai may be selectively read at will by means of selective dialunit on the master cabinet lit is a further object of this invention toprom vide an improved and accurate type or liquid depth indicatingsystem including a selectively operable remote control cabinet which iscon nectcd with a liquid control pressure device in a tank by means of atranslator unit including a W'heatstone bridge mechanism, one of thearms or which is adapted to have the eiective resistance thereof variedby means of a quenching liquid, the movement of which is controlled by apressure actuated mercury column, the movement of which is controlled bythe depth of liquid in the tank by means of the pressure unit in thetank. w Still another object of the invention is to provide a liquidlevel or depth indicating system, of a multiple type, readily adaptablefor use in connection with water ballast tanks or the bilge ofsteamships, whereby substantially accurate readings may b e read atremote stations or at a central station by connecting a commonindicating depth meter in a remote control cabinet with various tanks bymeans of a selective dial unit making it possible to positively selectany o! the tanks in the system for liquid depth measurement by means ofclosed circuit mercury control units connected with the indicatingmeter. The indicating units are respectively connected to individualpressure units in the rsepective tanks so that a pressure unit which isselectively connected in a circuit and operated upon by the liquid in aselected tank causes accurate actuation of a primary organic liquid bodyon a mercury control column which, in turn, controls the movement of anauxiliary column of an inert iluid to coact with a wire adapted to beheated when in circuit and forming an arm of a Wheatstone bridgearrangement to unbalance a normally balanced circuit adjustment thereofin direct proportion to the amount of iluid in the tank being measuredand operate the indicating meter' accordingly to cause the meter toindicate the depth of the liquid in the tank being measured.

It is furthermore an object of this invention to provide an improved andaccurate form of a liquid depth indicating system wherein a selectivelyoperable master control cabinet is connected with a pressure actuateddiaphragm mechanism in a tank in which liquid is to be measured, saiddiaphragm mechanism and control cabinet being connected by means of animproved translator unit involving a Wheatstone bridge mechanism, one ofthe arms of which comprises a wire mounted in free air, While anotherarm comprises a wire which is adapted to have the effective resistancethereof varied by means of a quenching effect produced by a movablecolumn of an inert organic liquid supported on a mercury column, themovement of which is controlled by the pressure produced by the amountof liquid in a tank acting on the diaphragm unit in the tank.

It is an important object of this invention to provide an improved andaccurate type of liquid depth indicating system wherein a closed.circuit translator unit is disposed between the contents of a containerto be measured and a selectively operable master control cabinetincluding a depth indicating meter adapted to be set at zero readingwhen the tank is empty to provide a circuit which is in electricalbalance and which is thrown off balance by an amount depending upon thequantity of liquid in the tank which acts on a pressure operateddiaphragm unit in the tank to s simultaneously operate rst a pressuretransmitting primary liquid body and then superimposedliquid columns,one of mercury and the other of an inert organic liquid, to cause saidinert organic liquid to coact with a slightly heated high temperaturecoefiicient wire forming part of a Wheatstone bridge arrangement of thetranslator unit to quench or submerge a portion of said wire in amountsdirectly proportional to the liquid in the tank being measured to causeunbalancing of the Wheatstone bridge balanced circuit by changing theeffective resistance of the partially quenched wire thereby permittingthe change in resistance caused by the unbalancing of the Wheatstonebridge circuit to be read on the indicating meter at the remote controlcabinet thereby permitting a substantially instantaneous reading to beobtained of the liquid depth in a selected tank.

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawings.

The invention, in a preferred form, is illustrated in the drawings andhereinafter more fully described.

On the drawings:

Figure 1 illustrates a schematic arrangement, partly in elevation andpartly in section, of a multiple type of a liquid level depth indicatingsystem embodying the principles of this invention and applied to aplurality of liquid containing compartments or tanks such as the waterballast tanks of a ship, for the purpos: of readily ascertaining thelevel or depth of the contents of the various tanks selectively, by aselective operation of a remote control cabinet through a particulartranslator unit connected with a diaphragm control means within the tankselected to be measured.

Figure 2 is an enlarged vertical sectional view of the pressure actuateddiaphragm unit taken on line II-II of Figure 1.

.Figure 3 is a fragmentary top elevational view of the pressure controldiaphragm unit taken on line III-III of Figure 1.

Figure 4 is a fragmentary elevational view of the translator cabinet,with the door in open position, and illustrating the mechanism in theinterior of the cabinet arranged for connection with a group of from oneto four tanks.

Figure 5 is a vertical sectional view through the insulation translatorcabinet taken on line V-V of Figure 4 and illustrating the thermostaticcontrol circuit arrangement for the heating device to control the samefor maintaining a predetermined constant temperature within thetranslator cabinet.

Figure 6 is an enlarged fragmentary elevational and sectional view ofthe lower portion of one of the translator units and illustrating thenormal level of the mercury in the mercury well and the normal level ofthe column of inert organic liquid supported on the mercury and operablein a stand tube leading from the mercury well.

Figure 'I is an enlarged fragmentary elevational and sectional view ofthe upper portion of one of the translator units with a portion of theWheatstone bridge mechanism broken away.

Figure 8 is an enlarged fragmentary elevational and sectional view takensubstantially along the line VIII-VIII of Figure 7 and showing inelevation the portion of the Wheatstone bridge mechanism omitted inFigure 7.

Figure 9 is an enlarged sectional view taken on line IX--IX of Figure 6showing the open end of one of the tubes.

Figure 10 is an enlarged transverse sectional view taken on line X-X ofFigure 7.

Figure 11 is a circuit diagram for the remote control cabinet and forone of fthe translator units connected with the cabinet circuit througha selectively operable electric stepping switch unit to which the othertranslators of the system are also connected. g

As shown on the drawings:

This invention relates to an improved and simplified form of a liquidlevel or depth indieating system conveniently adapted for use inselectively measuring the depth cf liquid in a series of tanks orcontainers, such as the water ballast tanks of a ship, by means of aremote control cabinet which may be located in the pilot house or anyother convenient place on a ship, said control cabinet being connectedwith the various ballast tanks of the ship by -means of a plurality oftranslator units, one for each of the tanks, said translator units beingmounted within a constant; temperature translator cabistant temperaturewithin the cabinet.

i supported slightly above the bottom of the respective tank in positionto be operated on by Y the pressure exerted by the liquid content of thetank.

be coniined primarily to the schematic form of the system illustrated inFigure 1 directed to asingle translator unit and its respectivediaphragm mechanism mounted 'within a particular tanlz. e translatorcabinet, however, is illustrated lor a multiple systemy yincluding fourtranslators which: are respectively connected with four separate tanks.The group of translators are also connected with a standard type of`electric stepping switch mounted in the upper portion of the translatorcabinet and connected with the selectively operable remote piontrolcabinet of 'fthe system. It will, of course, be understood that anynumber oi tanks may be included in the system. and that the number ofdiaphragm units and translator units will correspond with the number oftanks.

Referring more particularly'to the schematic Aarrangement illustrated inFigure 1 oi the drawings, the reference numeral l indicates a containeror tank containing a liquid E, the level or depth ci which is 'to bemeasured and registered on an indicating meter in the remote controlcabinet of the system. Secured on the bottoni ci? the tank or in anyotherconvenient position within the tank is a supporting bracket il, towhich is rigidly secured a supporting arm is one end ci which is boltedor otherwise secured to the top ci' protecting cover or hood constructedof cast iron or other suitable material audihelo; in position a slightdistance above the hottcrn ci the tank i to permit liquid. in the tankto flow upwardly into the hood. Mounted within the protecting cover orhood and clear ,of the bottom oi the tank, is a hollow bellows diaphragmd preferably constructed ofvphosphor bronze or inverse Monel metal: Thevbellows diaphragm is 'placed in the tank at the lowest point from whicha reading is desired. The hflcur bellows diaphragm ti filled with air oran "'iert gas, which, when compressed by the i d in the is permitted tobe forced out of the diaphragm into a small bore copper tube, one oiwhich is connected to a suitable point in the diaphragm. The pressuretube connected with the diaphragm is designated bythe reference numeral'I .and leads upwardly out of the 'rtank i and from there is conductedto lead into a translator cabinet il which may be situated near thetanks or on an upper deck of the ship where the translator cabinet maybe conveniently accessible. The entire translator cabinet 8 isconstructed of an insulation material including a door Si which, whenclosed, has a tight fit with the cabinet housing. The. translatorcabinet 8 is provided with a transverse shelf or partition lil near theupper portion thereof to divide the interior of the cabinet into anupper chamber Il and a lower translator chamber I2.

In order to insure a more eiiicient operation of the system it isdesired to maintain a con- I For accomplishing this purpose, an electricbulb or heating unit lIll is mounted on the bottom of In order to'simplify the description of theliquid level depth system, thedescription will met s and is connected to a standard piug which thechamber I2. Connected to one terminal of the heating unit- I3 is one endof a wire I4, the other end of which ls connected to one terminal of astandard type of thermostatic switch I5 mounted within the translatorcabinet chamber I2. Connected to the other terminal of the thermostaticswitch I5 is one end of a wire I6 which is conducted out of thetranslator cabis inserted in an electric power socket. The secondterminal of'the heating unit i3 has connected thereto one end of a wireIl which also is conducted out of the cabinet 8 and is connected to theplug to which the wire i6 is at- For the purpose of causing a propercirculation of the air within the lower chamber `I2 of the translatorcabinet, an air circulating tube or sleeve i8 is supported by means-of a'bracket is, the lower end .being lpositiouedover the heating lunit I3.to facilitate the proper cire culation of the heated air within thecompartment I2 of the translator cabinet.

Mounted on suitable insulation brackets on the back wall of thetranslator cabinet 8 and Within the lower chamber I2 thereof are aseries of four translator units A, B, C, and D, one for each of fourtanks included in a system of liquid containingr tanks, the Vdepth ofthe liquid of which it is desired to be able to quickly readselectively, at either a station adjacent thetanks or at a remotecontrol station, by means or a master control cabinet 20 of the systemas installed. While only four translatorn runits are shown in thecabinet 3 in Figure li, it will, of course, be understood that anynumber of translators may be provided depending upon the number of tanksin a system requiring liquid depth measurement readings, the number oftranslators, of course, depending upon the number of tanks, since onetranslator is required for each of he tanks to be measured.

Since only one translator and tank is illustrateci in the schematicdiagram illustrated in Figure l, the details of the translator i willnow be described. Y

Referring now to Figures 5 to il) inclusive, each of the translatorunits comprises a connecting tube 2i constructed of brass or othersuitable material into the upper end ci which an end of the pressureconducting' tube "l, e ling from the diaphragm in the tank i, proiects.rubber insulation sleeve or collar 'lil is engaged around the connectionbetween the tube and the tube 2l to insure an airtight iitbetween saidtubes. The lower end ci the connecting tub` has an airtight fit with acoupling nut l@ which, in turn,

is `tightly threadedinto the upper end of a pressure stabilizing tube orpipe 2t. The pressure equalzing pipe 21% provides an expansion chant ber25, the lower end of `which communicates with a restricted opening 2Sformed in the lootu Atom of the tube 24 in'position to communicate withthe upper end of a restricted or small diama normal level indicated bythe arrow E (Figure 6).

Engaged in the manometer above the mercury 30 is a quantity of a mobileinert organic liquid 98 which iills the manometer well 28 and projectsupwardly filling the restricted tube 21 and extends upwardly into theexpansion or pressure stabilizing pipe 24 to form a primary liquid co1-umn, the normal level within the pipe 24 being indicated by the arrow F,when the liquid tank is empty. The primary column formed by the liquid98 serves as a pressure transmitting column for transmitting thepressure from the chamber 25 of the pipe 24 to the mercury 30, and saidliquid 98 passing from the pipe 24 through the restricted passage of thetube 21 acts as a dampening medium for stabilizing any turbulent orpulsating pressures which may be transmitted by the diaphragm due to theagitation of the water in the tank caused by the rolling or tossing ofthe ship or from other causes.

The pressure expansion area in the upper portion of the chamber 25 ofthe expansion tube 24 is disposed between the pressure transmitting tube1 and the primary liquid column 98 and is provided for the purpose ofassisting the liquid column 98 in minimizing the accidental fluctuationsin the diaphragm transmitted air or gas pressures.

Projecting down through the top of the mercury well 28 and rigidlysecured to said well by solder or other suitable means is a mercuryoutlet pipe or tube 3| constructed of stainless steel or other suitablematerial. The mercury outlet tube 3| extends into the well 28, throughliquid head 98, a distance suilicient to permit the lower end of thetube 3| to project into the mercury 30.

The mercury 30 in the well 29 ows upwardly into the lower end of thetube 3| as a mercury column and supports a column of a mobile inertorganic liquid 32, such'as dimethoxy tetraethylene glycol. The auxiliaryor second inert organic liquid column 32 projects upwardly out of thetube 3| into a main tube 33 having a mounting base 34 secured on theupperend of the tube 3|. When the liquid tank is empty and the mercuryis at normal level E as shown in Figure 6, the normal level of the inertorganic liquid auxiliary column 32 is at the same level as the rstliquid column 98 as is indicated by the arrow F in the main tube 33.

As liquid is added into the tank pressure is exerted on the diaphragmwhich, in turn, will be compressed in accordance with the pressureexerted thereon and will transmit the pressure from the tube 1 rst intothe expansion chamber 25 of pipe 24, then to the liquid 98, and next tothe mercury well 28 to cause the mercury to rise in the pipe 3|. Whenthe tank is full, the upper end of the mercury column will rise in thetube 3| and extend to the point indicated by the arrow G. At this pointthe upper end rof the mercury column-Will actuate the needle valve 35 toseat against a valve seat 99 in the base 34 of the pipe 33 to preventthe further rise of the mercury into the tube 33.

Mounted adjacent the main tube 33 and sweat soldered or otherwiserigidly secured thereto for the entire length is an auxiliary tube 36,the upper end of which is level with the upper end of the tube `33. Thelower end of the auxiliary tube 36, however, stops short of the lowerend of the tube 33 and is open at the bottom. The two tubes 33 and 35are constructed of brass or other suitable material and have solderedthereto a nut 31.

Adjustably supported in the twin guide tubes 33 and 36 by means of anadjusting screw 33 and an upper nut 39 is a portion of a Wheatstonebridge. The portion of the Wheatstone bridge mechanism which is slidablymounted in the twin tubes 33 and 36 comprises a pair of tubes 4l and 4|which are slightly spaced apart and have the upper portions thereofconnected by a soldered connection 42. The upper nut 39 is also solderedbetween the two tubes 40 and 4|, as shown in Figure 7. Starting at apoint below the upper end of each of the tubes 49 and 4| is alongitudinal slot 43 which extends longitudinally downwardly through thelower end of the respective tubes 4|) and 4|. 'Ihe two tubes 49 and 4|respectively telescope into the supporting tubes 33 and 36 and areadapted to be held in a set position of adjustment by means of theadjusting screw 38 and the nuts 31 and 39.

Two arms of the Wheatstone bridge are formed by two wires 44 and 45,each having a very high temperature coeilicient of resistance andconstructed of nickel or other suitable material. To hold the respectiveWheatstone bridge wires 44 and 45 axially spaced within the respectivetubes 49 and 4|, a plurality of spaced mica disks 46 are secured to saidwires by means of an insulate cement. Soldered to the lower end oi' eachof the bridge wires 44 and 45 is a metal end disk 41 having a segment0|.' V-shaped notch 48 formed therein to serve as an entrance for theauxiliary column liquid into the tube 4|) from the tube 33. The slot 43in the tube 49 also permits the upper or bridge control iluid column 32to pass into the tube 49 and furthermore serves as a means for mountingthe wire 44 and the spacer disks thereof within the tube 40. The slot 43in the tube 4| serves as a means for mounting the wire 45 and its disks46.

Each of the Wheatstone bridge wires 44 and 45 has the upper end thereofsoldered or otherwise rigidly secured to the lower end of a nickel rod49 which, in turn, has the upper end thereof secured in the lower end ofa brass tube 50 which projects upwardly out of the upper end of therespective tube 40 or 4 Each of the brass tubes 59 has a pair ofinsulating tubes 5| cemented thereon to serve as spacing means betweenthe respective tubes 40 and 4| and the brass tubes 50 engaged therein.Rigidly secured in the upper end of the tube 50 associated with theWheatstone bridge tube 40 is a nickel terminal rod 52. A similar nickelterminal rod 53 is engaged in the upper end of the tube 50 associatedwith the Wheatstone bridge tube 4| The second half of the Wheatstonebridge mechanism consists of a split tube supporting bracket 54, thelower end of which is flattened out to form a plate 55 which is solderedor otherwise rigidly secured to the two tubes 33 and 36, as clearlyillustrated in Figures 7 and 8. Fric tionally engaged over the upper endof the split tube bracket 54 is a brass supporting tube 56, on which aporcelain spool 51 is cemented. The second half of the Wheatstone bridgearrangement comprises two balanced coils 58 and 59 constructed of wireconsisting of a copper, nickel and manganese alloy known to the trade asManganin. The Wheatstone bridge wires 58 and 59 are coiled in parallelaround the poreclain spool 51 (Figure 8) and are held in place at spacedintervals by insulate cement. At the lower end of the spool 51, the twowires 58 and 59 connect up selection.

with a common lead wire lill.l The point where the Wheatstone bridgewires 58 and 59 join the wire Il! is designated by the letter H, whichis one of the four points of the Wheatstone bridge formed by the wires58, 59, and 44, 45,`as more clearly illustrated in the circuit diagramshown in Figure 11. The Junction of the bridge Wires Il and 44 isdesignated by the letter I, and the junction of the bridge vwires 59 and45 is designated by the letter J. The junction of the bridge wires. and45 is-indlcated by the letter K.

Engagedin the upper part of the tube 33 and communicating with the airchamber in said tube is a small vent or breather tube 64 to allow forbreathing. Engaged on the outer end of the breather tube S4 is a bulb orbladder 65 to keep outside air from entering the tube 33 but stillallowing barometrlc pressure to be impressed upon the column ofinertorganic liquid 32 within the tube 33.

Referring now tothe circuit diagram shown in Figure l1, the Wheatstonebridge terminal K has connected thereto one end of a wire El. The Wires:63 and El connect the end terminals H and El of the Wheatstone bridgeacross the battery 'or power source of the circuit. Connected to theWheatstone bridge terminal I is one end of a Wire EE, and a wire 63 hasone end thereof connested to the Wheatstone bridge terminal J. These arefour wires 60, El, 62, and 63 forming a small cable and leading fromeach of the translator units mounted in the translator cabinet 'oupwardly through a suitable opening in the par titi-cn shelf i3. Thefour wires of each of the snr. il cables are connected to an AutomaticElec trio Gompanys type of standard multiple point, rotary steppingswitch 66 mounted in the upper chamber li of the cabinet t. The meinstepping switch 66 includes a plurality' of bridging switch Wipers @lwhich are mounted side by side on a rotatable wiper shaft and coact witha plurality of separate contact levels Sii, 9S, lli, and li. Anadditional homing switch wiper l2 is included in the stepping switch forcoection with a homing level 'lil to permit homing operation, forautomatically returning the wipers to a home position after use.

homing operation of the wipers 6l, is accomun plished hg means ofautomatic rotation through the medium of the release magnet lo and thebattery d3 which together with the monitor switch "Srl forms a, releasecircuit. lifter the Wipers have been selectively set by use of the dialtype pulsating device lf2, the release circuit is closed by manualoperation of the Ymcnitor switch Si, This closing of the release circuitcauses the wipers 6l to be rotated toward home position, and when saidposition is reached, a set of off-normal springs, forming part of thestandard homing type switch, act to open the release circuit when thewipers reach the home position, thereby permitting the wipers 6l toremain in home. position ready for another selective operation by use ofthe dial device lit A similar arrangement is also provided for causingthe uppermost wiper 1l of the light control standard homing type ofstepping switch 'to return to home position to extinguish the pai:-uticular indicating light 'I9 which was lighted when the dial device wasoperated to make a circuit Homing of the light control upper wiper il isaccomplished by automatic rotation 94 form a release circuit for controlof the indicating lights.' The closing of the light control releasecircuit by the manual operation of monitor switch 94, causes thelowermost and uppermost wipers 11 to be rotated toward home position andwhen said position is'reached a set of off-normal springs forming partof the light control'stepping switch, act to open the light controlrelease circuit, thereby permitting the wipers Il to remain in homeposition ready for another selective operation of a light when the dialdevice 14 is again operated to make another circuit selection forobtaining a'liquid depth readlng in a selected tank.

The stepping switch permits of a selection of one particular circuit ofa group of translator circuits, and said selection is accomplished andcontrolled by means of 'a standard type automatic telephone selectivelyoperable impulse sending dial desk unit 14 mounted in the remote controlcabinet 20.

Included in the stepping switch 66 is a stepping magnet 'l5 connectedwith the homing wiper 'l2 and with a stepping magnet 'i6 and also to thelowermost wiper El forming part of an indicating light control,automatic standard rotary stepping switch. The light control steppingswitch, which includes a plurality of wipers 'Il and levels i8, ismounted in the remote control cabinet 2li and selectively governs theoperation of a plurality of lettered or numbered indicating lamps orlights 't9 for designating the particular "3 are used in the circuit.

through the medium of the release magnet 18, y

the lowermost wiper TI, the level 'i8 and the battank to be measured forliquid depth and the translator unit connected with the diaphragm unitof the selected tank.

In the light control' stepping switch only the lowermost and uppermostWipers 'il and levels The intermediate Wipers 'il and levels 'I8 are notused.

The lamps or lights 19 are mounted in a lamp jack strip ttl mounted inthe front panel of the control cabinet 2d. The numbebof lights inservice depends upon the number of tanks in the `liduid level or depthindicating meter d2 is mounted. A panel light 83 is mounted ou the frontpanel of the cabinet 20 over the meter t3 to illuminate the dial of themeter when the system is in service.

The indicating meter 82 is a double purpose instrument functioning as anammeter in the battery circuit across the terminals H and li of theWheatstone bridge, and as a voltmeter in the galvauometer circuit acrossthe terminals l and J of the Wheatstone bridge. A double pole, doublethrow lever key operated input and output switch 84, connected in thebattery side of the circuit, controls the meter 82. The switch Sil ismounted in the control cabinet Ztl and is controlled by a lever key 8lon the front panel of the cabinet 20. l

The meter S2 may be used either as an ammcter or a Voltmeter and may beconnected in the circuit to give either input or output readings. Thisis done by use of the switch 84. When the switch key 81 is moved toinput the meter 82 is connected for use as an ammeter to check on thebattery voltage and to measure the input to the translator from thebattery. The input reading should read a predetermined amount, say 205inches on the meter scale. If the meter does not read 205 inches it canbe adjusted by adjusting the rheostats 85 and 86. The rheostat 85 is of26 ohm capacity for coarse adjustments and the rheostat 88 is of 2 ohmcapacity to permit of iine adjustments.

The small resistor shunted across the circuit wires connected to theinput contacts of the switch 84, is about .1 ohm resistance and isessentially an ammeter shunt for controlling the flow of current to thebridge. The second small resistor connected in the circuit wireconnected to one of the output contacts of the switch 94 is about .2 ohmresistance and is used to compensate for variation in line resistance.

The switch key 81, when thrown into the up or finput position, connectstwo rheostats 85 and 86 in circuit. The rheostat 85 is for coarsecontrol, and the rheostat 88 is for ilne adjustments. The rheostatarrangement enables adjusting of the current ilowing through atranslator unit to a given or selected value to cause properenergization of the Wheatstone bridge forming part of a translator unitin case the bridge should at some time get slightly off balance for somereason during the use of a translator. By throwing the lever key 81 toinput also permits of a check-up on the voltage of the circuit battery 188 connected across the terminals 89 and 99 of the circuit.

When the switch key 81 is thrown down or Into output position, the meter82 is connected across the Wheatstone bridge terminals I and J and actsas a galvanometer for liquid depth reading of the liquid in the tank Iselected for liquid depth measurement. When the lever key 81 is movedinto the output position, a push button switch 9|, designated Record,should simultaneously be operated to shunt the meter across the wiresconnected with the output yterminals of the switch 84, to permit themeter to be used as a voltmeter thereby causing the meter 82 to indicatethe depth oi the liquid in inches for a selected tank.

To connect the remote control cabinet 29 in the system, a main controldouble contact switch 92 is mounted in the cabinet 20. When the switch92 is in "oiT position, both the electric circuit 93 for the meter panellight 83 and the battery circuit for the system are open. To use thesystem, it is only necessary to move the main switch 92 to on position.The panel light circuit 93 will then be closed, as well as the batterycircuit for the system. With the closing of the light circuit 93, thepanel light 83 will light up to illuminate the face of the instrumentpanel of the control cabinet.

If one of the indicating lamps or lights 19 in the lamp jack strip 89 oneither side of the remote control cabinet panel should happen to belighted at the beginning of a test operation, the button of a monitorswitch 94 is pushed in and held down until all buzzing ceases and all ofthe indicating lamps 19 are extinguished. The buzzing is caused by thewipers of the homing switch moving over the switch contacts whenreturning to home position.

Connected in the battery circuit is a bridge opening control slowrelease relay 95, which is connected in parallel with a quick actingrelay 91 and its resistor 96. The relays 95 and 91 are connected throughthe off normal contact spring of the selector dial desk unit -'I4 tobattery, whenever the dial unit is operated. Relay 95 opens the circuitto the bridge to keep all pulses or surges off of the bridge whiledialing takes place.

The relay 91 connects the pulsing spring ot the dial unit to the magnetsof the stepping switches.

Relay 95 holds the bridge circuit open during dialing, to protect theinstrument circuit and also does away with sparking at the steppingswitch contacts, as the wipers pass over the contacts during the returnmovement of the dial.

Relay 95 is energized when the dial unit is operated. The movement ofthe dial causes alternate making and breaking of the otr-normal contactspring of the dial unit 14, thereby completing a circuit through thebattery for energizing the relays 95 and 91. Relay 95 when thusenergized actuates its armature to break the circuit to the bridge.Relay 95 being slow acting does not allow its armature to drop back dueto the rapidity with which line relay 91 operates. When the dial makesits return movement, the circuit through the relay 91 is interruptedcausing the armature of the relay 91 to drop back as each projection ortooth on the dial is contacted. With each dropping back of the armatureof the relay 91 the stepping switch is operated one step. Theinterruptions due to rotation of the dial are too rapid to permitrelease of the armature of the relay 95 until the whole series ofinterruptions has been sent and the shaft of the stepping switch hasbeen rotated the required amount w connect a selected tank in circuitfor taking a liquid depth reading.

Each of the separate translators in the translator cabinet 8 isconnected to its respective diaphragm in a particular tank. The varioustranslators are each connected by a, separate small four wire cableleading from the Wheatswne bridge terminals of the translator to themaster stepping switch 66 in the upper chamber of the translator cabinet8. A master cable connects the master stepping switch 66 to the remotecontrol cabinet 20 and said master cable includes eight wires, seven ofwhich are in use while the eighth serves as a spare.

Having described the various mechanisms and the circuit for the liquiddepth indicating system, a brief description of the system will now begiven. The system is applicable for use with one or with a plurality ofliquid containing tanks, with each of the tanks in the system beingequipped with a bellows type diaphragm unit mounted in the tank andbeing connected by the pressure tube with a particular translator unitmounted in a translator cabinet, which may be located near the tanks orat a remote distance therefrom, said cabinet also containing a masterelectric rotary, stepping switch 68 of a standard type and of a selectedcapacity depending upon the number of tanks with which the system isconnected.

In order to insure eiiicient operation of the system, the temperaturewithin the translator cabinet 8 is maintained at a predeterminedconstant by means of the thermostatically controlled heating lamp orunit I3 with which the heat circulating tube I8 is associated.

For the purpose of conveniently obtaining substantially instantaneousdepth or level reading of the liquid in a selected tank of the system,thev remote control cabinet 20 may be conveniently located at anyselected distance from the translator cabinet, and if the system isconnected with the various ballast tanks of a ship, the control cabinetmay be located in the pilot house or in any other convenient place.

With the system installed as described, an operator of the device hasmerely to determine which of the tanks he wishes to know the liquiddepth of. The selection is made by means of the selector dial unit 14.The 'main control switch $2 is rst moved into the onf position therebycausing lighting of the 1amp as to illuminate the instrudialing theparticular tank number. This dialing operation will light up "thecorresponding lamp 19 thereby clearly indicating the tank which is beingmeasured.

In case thereare more than ten tanks in the` system, the tanks above No.10 indicated by the lamps in the lamp jack strip, in the right hand sideof the cabinet 20, may be selected by dialing the number plus ten. f

lf it is desired to check on the system, `the switch lever key of theinput and output switch lit is pushed into the input position to give achecll: on the battery voltage and a measure of the input to thetranslator unit from the battery. in case ythe meter t2, which is nowconnected for use as 'an ammeter, does not give a selected predeterminedreading, the meter can be adjusted to the required value by means of theproper adjustment of the coarse control rheostat t and the uneadjustment control rheostat 86.

With the checking of the instrument as described, the operator is nowready to obtain the liquid depth reading of the tank being measured. Todo this, it is only necessary to move the lever hey 8l into the down oroutput position, thereby connecting the meter 82 across the lifheatstone'4G bridge of the selected translator to cause the meter to act as agalvanorneter. Simultaneously with the operation of the key lever Elinto the output position, the button of the Record switch is pushedinwardly. The meter will now indicate the depth of the Water i inches ofthe taule whose number is illuminated. w

When the foregoing operation taires place, the amount oi' water in thetank i acting upon the pressure diaphragm t will cause theproducedpressure to transmitted through the pressure tube l into theexpansion pipe chamber 25 allowing the pressure to expand and actagainst the primary liquid column St to force the same same through therestricted tube 2i' and then into the manometer thereby causing thetransmitted pressure to be stabilized to obviate any disturbing effectwhich might be produced by the violent agitation or water in the tankbeing measured. The transmitted pressure from the expansion pipe 2t isdelivered by means of the priy mary liquid column 98 through therestricted pressure pipe 2l and then into the upper chamber of themanometer or mercury Well 28. The pressure transmitted into themanometer is applied to the top surface of the mercury 3i) by the liquidhead 98, thereby causing the mercury to rise in the stand tube 3|, tocause an upward movement of the auxiliary or quenching column 32 of theinert organic liquid, so that the auxiliary column 32 will move upwardlywithin the main tube 33 forming part of the Wheatstone bridge mechanism.The liquid. 32 rises in the tube 33 and passes upwardly in the tube 40around the wire 44 forming one of the legs of the Wheatstone bridge, therise of the auxiliary column in the tube 40 being directly proportionalto the pressure exerted by the water in the tank I on the diaphragm 6.The Wheatstone bridge wires 5 44 and 45, which are of equal length andform two of the arms of the Wheatstone bridge arrangement, will beheated, when the circuit ls closed, due to the flow of current, but thewire 44 in the tube 40 will be quenched by the inert organic fluid 32 inamounts directly proportional to the depth oi the liquid in the tank I.The wire 4l in the tube 4|, when heated, however, does not have theeffective resistance thereof changed, since the wire is suspended infree air. 'Ihe quenching or immersing of the wire 44 accordinglyunbalances the normally balanced Wheatstone bridge circuit in an amountdirectly proportional to the pressure exerted on the control diaphragmdue to the relative difference of the resistance of a ,heated Wire infree air and a similar heated Wire which is partially quenched. The

change in resistance due to this phenomenon is accordingly adapted to beread on the galvanometer scaie which will accurately indicate the depthor level of the liquid in the tank being measured. When the tank i isfull, `the pressure exerted on the control diaphragm is such that theliquid column 98 acting on the mercury il@ will cause the same to risein the tube iii to the level ln- 3g dicated by the arrow G, at whichpoint the upper end of the mercury column will engage the needie valve(Figure 6) to seat the head of the valve against the valve seat 99provided in the mount-a ing' base 34 of the tube 33, thereby eiieetiveiy35 stopping any further rise .of the mercury column. If the tanlr. isfilled to overowing, the needle valve 35 will, of course, be closed asdescribed, and the apparatus will cease to function.

The improved liquid depth indicating apparam tank or a plurality oftanks, and it is immaterial `wlfiether the tanks to be measured containwater, or a volatile duid or liquid, since there is no danger as Iall ofthe electrical contacts are at a remote distance from the tanirs beingmeasured. By means of the remote control board and the selective dialunit 'lia depth readings of the liquids in a plurality of tanks may beeasily and quickly1 read on the indicating meter in any selectedsequence desired by a proper dialing of thelnstrument lfl.

t will, of course, be understood that various details of constructionand arrangement of the elements of the system may be varied through awiderange without departing from the principles of this invention, andit is therefore not the purpose to limit the patent granted hersenotherwise than necessitated by the scope of the appended claims.

What is claimed is:

l. ln a liquid depth indicating system for indicating the depth ofliquid in a tank., and with said system including a. translator unitconrprising a manometer, mercury in said manometer, a stand'tube in themanometer and projecting therefrom and providing a guide for e. columnof` theY mercury, a pair of primary tubes fastened together in parallelrelation with one of said primary tubes secured on the upper end of thestand tube, an upper column of an inert organic liquid supported on themercury column and projecting up into the primary tube secured to thestand tube, and a Wheatstone bridge mechanism supported on the primary75 tubes and including a pair of secondary tubes tus may be arranged.for the measuring of a single telescoping into the primary tubes, abridge arm wire in each of the secondary tubes and insu-l latedtherefrom, said wires being connected at their lower ends to the tubes'in which they are mounted, an insulation spool mounted on the exteriorof the primary tubes, a pair of bridge arm coils supported on theinsulation spool and connected to the bridge wires in the secondarytubes, said bridge coil arms connected to one another, said column ofinert organic liquid movable by the pressure actuated mercury column upinto one of the secondary tubes to pro- A duce a quenching action on thebridge arm wire contained'therein to vary the effective resistance ofsaid bridge arm wire to unbalance the Wheatstone bridge for determiningthe depth of the liquid in the tank.

2.'In a, liquid depth indicating system for determining the depth 'ofliquid in a tank and including a gas-filled closed diaphragm in thetank, a translator unit connected with the diaphragm to be actuatedthereby, said translator unit comprising a manometer, an expansion tubeconnected at one end with the diaphragm, a restricted tube connectingthe other end of the expansion tube with the manometer, a pressuretransmitting liquid in the expansion tube, the restricted tube and inthe manometer, a stand tube in the manometer and projecting therefrom,mercury in the manometer supporting said liquid and projecting upwardlyinto the stand tube to form a mercury supporting column, a pair ofconnected primary tubes one of which is rigidly supported on the standtube,

an inert organic liquid column supported on the mercury column andprojecting up into the primary tube supported on the stand tube, acontrol valve in the upper end of the stand tube operable only by themercury column into closed position to prevent the mercury column fromentering the primary tube supported on the stand tube, and a resistancebridge mechanism supported on the primary tubes and including a pair ofsecondary tubes telescoped into the primary tubes, bridge arm wires inthe secondary tubes with one of said wires disposed in the path ofmovement of the liquid column for varying the resistance of the bridgemechanism in accordance with the pressure delivered to the manometer, aninsulation support mounted on the primary tubes, and a pair of connectedbridge arm coils on the insulation support and connected with the bridgearm wires in the secondary tubes.

3. In a liquid depth indicating system for determining the depth ofliquid in a tank and including a gas-filled closed diaphlragm in thetank, a translator unit connected with the diaphragm to be actuatedthereby, said translator unit comprising a manometer, an expansion tubeconnected at one end with the diaphragm, a restricted tube connectingthe other end of the expansion tube with the manometer, a pressuretransmitting means in said tubes and in the manometer, a stand tube inthe manometer and projecting therefrom, mercury in the manometersupporting said means and projecting upwardly into the stand tube toform a mercury supporting column, a pair of connected primary tubes oneof which is rigidly supported on the stand tube, an upper column `of aninert organic liquid supported on the mercury column and projecting upinto the primary tube supported on the stand tube, a control valve inthe upper end of the stand tube operable only by the mercury column intoclosed position when the tank is full to prevent the mercury column fromentering the primary tube supported on the stand tube, a resistancebridge mechanism supported on the primary tubes and including a pair ofsecondary tubes telescoped into the primary tubes, bridge arm wires inthe secondary tubes with one of said Wires disposed in the path ofmovement of the upper liquid column for varying the resistance of saidwire to unbalance the bridge mechanism in accordance with the pressuredelivered to the manometer, an insulation support mounted on the primarytubes, a pair of connected bridge arm coils on the insulation supportand connected with the bridge arm wires in the secondary tubes, andmeans for adjusting and holding the secondary tubes in a set position ofadjustment with respect to the primary tubes.

4. In a liquid level indicator system for indicating the level of liquidin a tank, and wherein a closed gas-iilled bellows is placed on thebottom of the tank, a. translator unit connected with the bellows andcomprising a manometer including a mercury column, means connectedbetween the manometer and the bellows for stabilizing the pressuredelivered to the manometer, a resistance bridge mechanism supported onthe Y manometer, and a secondary column of an inert organic liquidsupported on the mercury column and operable therewith into resistancevarying engagement with one of the arms of the resistance bridgemechanism to unbalance the bridge mechanism proportionately to thepressure exerted in the manometer for determining the level of theliquid in the tank.

5. In a liquid level indicating system for determining the depth ofliquid in a tank and including a translator unit comprising a manometercasing, an expansion tube, a restricted tube connecting the expansiontube with the manometer casing, pressure transmitting means in saidtubes and in the manometer, mercury in the manometer and supporting saidmeans, a. stand tube in the manometer and projecting therefrom forguiding a column of mercury, a. pair of primary tubes secured togetherin parallel relation with one of the tubes secured on the upper end ofthe stand tube and the other tube being open at both ends, a column oforganic liquid supported on the mercury column and projecting into theprimary tube supported on the stand tube, a pair of connected secondarytubes telescoped into the primary tubes, means for holding the secondarytubes in a set position of adjustment with respect to the primary tubes,a high temperature coeflcient of resistance wire in each of thesecondary tubes and insulated from the tubes, said wires connected attheir lower ends to the secondary tubes, one of said wires positioned tobe acted upon by the column of organic liquid actuated by the mercurycolumn to cause variation of the resistance of said wire, a bracketsecured to the primary tubes, an insulation spool on said bracket, and apair of M connected Wire coils on the insulation spool with one of saidcoils connected to one of the wires in one .of the secondary tubes andthe other coil connected with the wire in the other secondary tube.

6. In a liquid depth indicating system including a. translator unitcomprising a manometer, two sets of telescoping tubes supported on themanometer, a pressure actuated mercury column in the manometer, asecondary liquid column of an inert organic liquid supported on themercury ondary column of liquid tounbalance the bridge.n

7. A liquid depth indicating system for selecrality of tanks, saidsystem including a plurality .of closed gas-iilled diaphragms konemounted within each of said tanks, a plurality of trans- `lator unitsmounted at a remote station, means for maintaining the translator unitsat -a constant predetermined temperature, one of said diaphragm unitsfor each of said translator units, each of said translator unitsincluding pressure operated superimposed columns ofyorganic'and metallicliquids, and a resistance bridge mechanism coacting with one,of theorganic liquid columns to be unbalanced thereby an amount.

proportionate to the pressure transmitted by the container forming lpartof the translator'unit, a.

columnf of a heavy metallic liquid and a column of a lighter organicliquid supported thereon tively measuring the depth of liquids ina'pluwithin the container, a pressure transmitting to transmit astabilized pressure to the heavy diaphragm connected with the translatorunit,

an automatic stepping switch unit connected with all of the translatorunits, a remote control unit connected with the automatic steppingswitch unit and including means for selecting and indicating a tank' tobe measured for liquid depth, rheostats for normal energiz'ation of theresistance bridge mechanism of the selected translator unit for aselected tank, and means for then indicating `the depth of liquid intheselected tank in accordance with the unbalancing of the resistancebridge mechanism due to the movement of oneV of the organic liquidcolumns into a resistance varying position with respect to theresistance bridge mechanism.

8. In a liquid depth indicating system for se-l lectively determiningthe depth of liquid in a plurality of tanks, said system including aplurality of gas-lled closed diaphragms one mounted Within 'each of saidtanks, a plurality of translator units one for each of said diaphragms,each of said translator units including a manometer portion enclosingalternating organic and metallic liquid columns and an electricresistance bridge mechanism to have the resistance thereof varied by theaction of one of the organic liquid columns; an automatic steppingswitch unit connected with all of the translator units, and a remotecontrol mechanism connected with the automatic stepping switch unit forselecting-and indicating a particular tank to be measured for liquiddepth and also including rheostat means lfor normally energizing theresistance bridge' -manometer means, a four arm resistancev bridgemechanism supported onthe manometer means, and an organic liquid columnsupported on the sistance varying engagement with one of the aims of theresistance bridge mechanism to unbalance a balanced setting of thebridge mechanism.

10. In a tank liquid depth indicating system wherein the pressure of theliquid in the tank liquid column to move the same and aotuate thelighter liquid column into coacting resistance varying engagement withthe balanced electric resistance means to 'unbalance the sameproportionate to the communicated pressure to cause an accurate liquiddepth reading to be indicated on the indicating means of the system byprevent.

ing the metallic liquid column from contacting the resistance means.

l1. In a liquid depth indicating system wherein liquid pressure isapplied to a diaphragm and is transmitted through a tube to permitliquid depth readings to be read on a meter through the medium of atranslator unit characterized by a manometer including a mercury column,pressure transmitting and stabilizing means on the manometer forstabilizing the pressure transmitted to the mercury column, an` electricbridge mechanism supported on the manometer, an auxiliary column of aninert organic liquid supported on the mercury column for operationthereby to move the auxiliary liquid column into coacting engagementwith the Vbridge mechanism to unbalance the same an amount proportionateto the communicated pressure exerted on the liquid columns to cause themeter to indicate the depth of liquid in the tank.

12. In a liquid depth indicating system wherein liquid pressure isapplied to a diaphragm and is transmitted through a tube member topermit liquid depth readings to be read on a meter through the medium ofan electric translator unit characterized by Wheatstone bridgevresistance elements, a manometer means, a restricted tube connectedwith the manometer means, an expansion pipe connected with therestricted tube and with the tubesmember, an organic liquid in theexpansion pipe, vin the restricted tube and in the manometer means,mercury in the manometer means actuated by the organic liquid totransmit pressure from the diaphragm to produce a mercury column in themanometer means, an inert organic liquid column in the manometer meanssupported on the mercury column and movable thereby into coactingrelationshipv with one of the resistance elements to change theresistance thereof an amount proportional to the communicated pressure,and rheostat means connected with the translator unit for setting theWheatstone bridge resistance elements in anormal balanced state prior tothe taking of a liquid depth reading on mercury column for movementthereby into rethe indicating meter of the system.

13. Ina liquid depth indicator system wherein the pressure of the tankliquid is applied to a diaphragm and is transmitted through a tube to aytranslator unit connected therewith and characterized by an expansionpipe connected with the pressure tube, a stabilizing liquid medium inthe expansion pipe, a reduced diameter tube leading from the expansionpipe and filled with said liquid medium acting to stabilize thetransmitted pressure, a manometer connected with the' reduced diametertube and also con- 9 isvapplied to a gas-filled diaphragm to be read on`a liquid depth indicating means through the taining a quantity of theliquid medium, mercury in said manometer supporting the liquid medium, astand pipe in said manometer and extending therefrom for receiving themercury therein in the form of a column, a pair of joined parallel guidetubes one oi which is supported on the stand pipe, an inert organicliquid column supported on the mercury column and extending up into thetube supported on the stand pipe, an electric resistance bridgesupported by said parallel guide tubes, a source of electrical energyconnected across two terminals of the bridge, a depth .indicating meterconnected across two other terminals of the bridge, and adjustableresistance means for energizing the bridge by using the meter as anammeter, said inert organic liquid column movable by the pressurecontrolled mercury column into resistance varying engagement with thebridge to unbalance the bridge and permitting the meter to be used as avoltmeter to indicate the depth of liquid in the tank.

14. In a liquid depth indicator system wherein the pressure of the tankliquid is applied to a diaphragm and is transmitted through a tube topermit liquid depth reading to be read on a meter by means of atranslator unit connected between the meter and the tube andcharacterzed by a manometer, a pressure actuated column of metallicliquid therein, concentric columns of organic liquid supported on themetallic liquid column, a balanced electric bridge mechanism acted on byone of the organic liquid columns to vary the resistance thereof tounbalance the bridge mechanism an amount proportional to the pressuretransferred by the diaphragm to the other of said organic liquidcolumns, and switch means for connecting the meter with the bridgemechanism to cause the meter to indicate the depth of liquid in thetank.

l5. In a liquid depth indicator system of the class described whereinpressure applied toa diaphragm in a tank is transmitted to produce aliquid depth reading on a meter by means of a translator unitcharacterized by a pressure stabilizing means connected with thediaphragm, a liquid holder connected to said stabilizing means, ametallic liquid column in the holder, organic liquid columns in theholder separated by and supported on the metallic liquid column andoperable by the transmitted stabilized pressure, and a resistance bridgesupported on the holder and acted on by one of the organic liquidcolumns to unbalance the bridge an amount directly proportional to thepressure transmitted by the diaphragm to move all of said liquid columnsto cause the meter to indicate the depth of liquid in the tank.

16. In a liquid depth indicating system for selectively determining theliquid depth of a plurality of tanks, one at a time and with said systemincluding a plurality of gas-filled diaphragms one mounted on the bottomof each of said tanks, a plurality of translator units one for each ofsaid diaphragms and operable by the pressure transferred by therespective diaphragms, a main stepping switch connected with all of thetranslator units, .a remote control cabinet, a depth indicating metertherein, a plurality of signals in the cabinet one for each of thetanks, an auxiliary stepping switch in the cabinet connected With thesignals and with the main stepping switch to the translator units forselectively indicating the tank selected for depth reading, and means inthe cabinet for selectively connecting the translator units by means ofthe iirst mentioned stepping switch to the indicating meter forobtaining individual liquid depth readings for the tanks.

17. In a liquid depth indicating system for selectively determining theliquid depth of a plurality of tanks, one at a time, and with saidsystem including a plurality of gas-filled diaphragms one mounted ineach of the tanks, a plurality of translator units one for each of thediaphragms, means for connecting each translator unit with itsrespective diaphragm, a main stepping switch, means for connecting thesame with all of the translator units, a remote control dial mechanism,a plurality of signals one for each of the tanks, an auxiliary steppingswitch connected to and controlling the signals, means connected withthe main stepping lswitch for indicating the depth of the liquid in thetank in which the selected diaphragm is located, means connecting saiddial mechanism and said stepping switches, each of said translator unitsincluding a pressure actuated manometer, a Wheatstone bridge mechanisrn,and superimposed columns of metallic and organic liquids with one ofsaid liquid columns coacting directly with a member of the bridgemechanism an amount proportional to the pressure transmitted to themanometer and the liquid columns therein.

MARY W. CONLEY, Executvix of the Estate of Victor H. Conley,

Deceased.

